Grade handling

[Thomas Charles CONWAY]

Hi

The mechanism for handling different grades of compilation seems to be
rather unwieldy, and difficult to maintain. I propose to change the way
we deal with grades as follows:

	- A grade should be a string made up of `.' separated components.
	- Each component specifies some compilation feature.
	- Features can be given in any order.
	- The empty string corresponds to the current grade "none".

Two ways of handling the grade come to mind:
	- Use a table which maps a grade component to a list of options to
	  set.
	- A separate "grade" type which is tuple of all the grade dimensions.

The former scheme seems like a good idea, since it is a minimal change, and
should be quite easy to implement.

The handling of grades in this form within the shell scripts should be quite
straight-forward.

Comments?

Thomas
-- 
Thomas Conway <conway at cs.mu.oz.au>
Nail here [] for new monitor.  )O+